Play Integrity's highest level of attestation features requires devices to be running a security update which is within a sliding window of 1 year.
LOTS of Android devices have not released a security update in many many years. This forces users to unnecessarily upgrade to higher end OEMs.
Google is effectively pushing out Xiaomi, Huawei, and many others that offer excellent budget options. Google is not just offering you the comfort of not having to fill out CAPTCHAs on your phone, most importantly they are playing monopoly.